Until now, different solutions for automatic operations have been tried, but unfortunately, these solutions have not quite been satsifactory. It is well-known to fit every spindle group section of a drawing machine with an automatic doffing and donning system. This system consists in laying down full bobbins on a conveying belt which is moving in the lower part of the machine and in taking the empty bobbin from it. At the end of the machine, a device supplies a conveyor belt with empty bobbins and removes full ones. Such a doffing and donning device is described in French Pat. Nos. 1,455,716; 1,498,137 and 1,514,211; in U.S. Pat. No. 3,398,519 and in German application No. 2,225,673. However, these prior art devices exhibit certain drawbacks. The doffing and donning system is permanently stationary and several systems are necessary for a single machine, so that the construction of the machine is more complex and higher in cost, because every doffing and donning system is used only for a short period.
Prior art doffing and donning systems associated with means such as a conveyor belt to lay on and remove full bobbins and to supply empty ones have been previously disclosed such as in German application no. 1,510,593 and French Pat. No. 2,136,816. However, there are still two separated means used, one for doffing and donning, the other for conveying. In addition, the travel of the conveyor belt is inevitably limited, usually it does not go beyond the drawing step. Therefore, it is necessary to provide additional means to convey full bobbins from the lower end of the belt to the control or packaging device and means to convey empty bobbins from the preparation device to the upper end of the belt. The conveyor belt may be replaced by receptacles associated with the doffing and donning system and moving along the machine or from one machine to another as described in French Pat. Nos. 1,421,449 and 1,599,640 and in U.S. Pat. Nos. 3,447,297 and 3,344,539. However, additional means for the supply of empty bobbins and for the removal of full bobbins must be provided or else these operations have to be carried out by hand.
French Pat. No. 2,139,508 relates to an automatic doffing and donning device for swing-arm winders. The doffing and donning system travels along the machine and is associated with a conveyor system comprising a locomotive and of cars travelling along the machine. The automatic doffing system lays down full bobbins in cars according to their succession on the machine. At the machine end, cars are laid on a carriage and transported to the control and packaging device. This device comprises three separated means, at least, for the doffing and conveying step which requires transshipment. In addition, neither means for automatic unloading in the take-up area, nor means for the placing of the empty bobbins in position on the machine are provided.